The description of the RIA core includes methods to be employed for assays of the several peptide and steroid hormones and cyclic AMP. The peptide hormones from rats and hamsters and GnRH receptor concentrations will be assayed in the laboratory in Evanston under Dr. Schwartz' direction. All steroid hormones, whether measured directly in serum or after chromatographic purification, cAMP, and peptide hormones from human subjects will be assayed in the laboratory in Chicago under the direction of Dr. Chatterton. Anti-rabbit gamma globulin serum will be produced in the laboratory on the Chicago campus and provided to both laboratories for peptide hormone assays. Antisera for RIA of progesterone, estradiol and testosterone will also be produced there. Uniform quality control preparations will be produced for all assays. All data generated in the RIA laboratories will be entered in the data base file in the IBM-XT computers located on each campus. Data will be filed according to Project and experiment. Quality control data for all assays will also be entered in a computer file for each type of assay weekly, and running means and CVs will be computed. The computers on each campus will communicate through the fiber optic lines installed for that purpose so that all data will be accessible for all investigators at all times. Gonadotropins and other peptides will be measured in a total of over 103,000 tubes and steroids and cAMP in an additional 25,000 tubes yearly.